package string;
/** StringBuilder的演示*/
public class StringBuilderDemo {
    public static void main(String[] args) {
        String str = "好好学习Java";
        //复制str的内容到builder中---好好学习Java
        //StringBuilder builder = new StringBuilder(str);
        StringBuffer builder = new StringBuffer(str);

        //append():追加内容---在末尾追加
        builder.append(",为了找个好工作");
        System.out.println(builder);//好好学习Java，为了找个好工作

        //replace():替换部分内容(含头不含尾)
        builder.replace(9,16,"就是为了改变世界");
        System.out.println(builder);//好好学习Java，就是为了改变世界

        //delete():删除部分内容(含头不含尾)
        builder.delete(0,8);//删除下标为0到7的
        System.out.println(builder);

        //insert():插入内容
        builder.insert(0,"活着");
        System.out.println(builder);//活着,就是为了改变世界



































        /*
        //StringBuilDer的创建方式:
        StringBuilder builder1 = new StringBuilder();//空字符串
        StringBuilder builder2 = new StringBuilder("abc");//abc串


        //String和StringBuilDer互转：
        String str ="abc";
        StringBuilder builder3 = new StringBuilder(str);//abc串
        String str2 = builder3.toString();

         */

    }
}
